Superconductors must be operated at a cryogenic temperature below their so-called critical temperature, as above this temperature the superconductor demonstrates only normally conducting behavior. High-temperature superconductors (HTS) such as YBCO (yttrium barium copper oxide) in particular exhibits especially high critical temperatures and can also carry comparatively high electrical currents. It is noticeable, HTS materials as a rule are ceramic materials, so that for mechanical reasons these usually have to be used in the form of strip conductors, thus band-shaped substrates coated with HTS material. HTS coated conductors (tapes) can be fabricated only with limited lengths, so that for important applications such as coils, there is a need to interconnect strip pieces of HTS coated tapes between themselves.
From DE 10 2012 218 251 A1, a superconductor structure is known that has linked strip pieces, in which strip pieces are arranged overlappingly with superconducting layers facing one another. Between the superconducting layers, a normally conducting material is arranged in a way that by the substantially long overlapping lengths no notable ohmic resistance is introduced. The gap at two abutting strip pieces as a rule runs perpendicular to the longitudinal (extension) direction. In one embodiment, however, it is provided that the gap between two abutting strip pieces, which overlap with the same additional strip piece, is formed at an angle of 5-30° to the longitudinal direction of the strip pieces. In this way, inhomogeneities of the critical current in proximity to the gap can readily be bridged. The gap is substantially straight.
U.S. Pat. No. 8,195,260 B2 discloses how to splice two superconducting wires with wedge-shaped edges to one another in an HTS joint, and to overlap them with superconducting straps.
Owing to the gap or the splice point of the strip pieces, according to the observation of the inventors, the current capacity of the respective superconductor structure is generally markedly limited. In addition, a notable power loss usually occurs at the gap or in the area of splice.